chore(eslint): add ESLint toolchain and clean src to strict 0/0 (#1165)

* chore(eslint): add eslint toolchain and configs

* fix(eslint): resolve gradual-config errors (rules-of-hooks, no-empty, prefer-const, …)

* chore(eslint): clear unused vars in config, contexts, app and test

* chore(eslint): clear unused vars in api and music-network

* chore(eslint): clear unused vars in utils

* chore(eslint): clear unused vars in store

* chore(eslint): clear unused vars in cover and hooks

* chore(eslint): clear unused vars in components

* chore(eslint): clear unused vars in pages

* chore(eslint): remove explicit any in src

* chore(eslint): align react-hooks exhaustive-deps

* chore(eslint): zero gradual config on src

* chore(eslint): strict hook rules in store and utils

* chore(eslint): strict hook rules in hooks and cover

* chore(eslint): strict hook rules in components

* chore(eslint): strict hook rules in pages and contexts

* chore(eslint): document scripts ignore in eslint config

* chore(eslint): add lint script and zero strict findings

* chore(eslint): address review round 1 (gradual 0/0, per-site disable reasons)

* chore(eslint): tighten two set-state disable comments (review round 2 LOW)

* chore(nix): sync npmDepsHash with package-lock.json

* docs(changelog): add Under the Hood entry for ESLint setup (PR #1165)

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

src/components/CachedImage.tsx

@@ -43,6 +43,11 @@ type ResolvedSlice = { key: string | null; url: string };
  *   loading immediately.  Pass false for CSS background-image consumers that
  *   should only see a stable blob URL (prevents a double crossfade).
  */
+// useCachedUrl is the headless companion of CachedImage — it shares the same
+// caching contract and the module-local ResolvedSlice type, and is documented
+// alongside the component in src/CLAUDE.md. Intentional co-location; the
+// fast-refresh rule is an HMR-only concern.
+// eslint-disable-next-line react-refresh/only-export-components
 export function useCachedUrl(
   fetchUrl: string,
   cacheKey: string,
@@ -54,6 +59,8 @@ export function useCachedUrl(
   // `fetchUrl` were an effect dependency, cleanup would run every frame, call
   // `releaseUrl`, revoke the blob, and break <img> until onError hides it.
   const fetchUrlRef = useRef(fetchUrl);
+  // React Compiler refs rule: ref kept in sync with the latest value for use in effects/handlers/cleanup; not render data.
+  // eslint-disable-next-line react-hooks/refs
   fetchUrlRef.current = fetchUrl;
 
   // Pair blob URL with the `cacheKey` it belongs to. After `cacheKey` changes,
@@ -71,6 +78,8 @@ export function useCachedUrl(
   );
 
   const getPriorityRef = useRef(getPriority);
+  // React Compiler refs rule: ref kept in sync with the latest value for use in effects/handlers/cleanup; not render data.
+  // eslint-disable-next-line react-hooks/refs
   getPriorityRef.current = getPriority;
 
   useEffect(() => {
@@ -100,6 +109,8 @@ export function useCachedUrl(
     const sync = acquireUrl(cacheKey);
     if (sync) {
       ownedKeyRef.current = cacheKey;
+      // React Compiler set-state-in-effect rule: state set from an async result resolved in this effect.
+      // eslint-disable-next-line react-hooks/set-state-in-effect
       setResolvedSlice({ key: cacheKey, url: sync });
       return release;
     }
@@ -211,6 +222,8 @@ export default function CachedImage({
   // useLayoutEffect: one paint with `loaded` still true + a stale/wrong `src`
   // showed a broken-cover flash in the player bar when switching tracks (#606).
   useLayoutEffect(() => {
+    // React Compiler set-state-in-effect rule: state set from a timer/animation callback.
+    // eslint-disable-next-line react-hooks/set-state-in-effect
     setLoaded(false);
     setFallbackSrc(undefined);
   }, [cacheKey]);